Company A signed a sales contract with a foreign buyer for e

Company A signed a sales contract with a foreign buyer for exporting Tea Sets,under FOB term.At t
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不好意思，没检查，
Company A signed a sales contract with a foreign buyer for exporting Tea Sets,under FOB term.At the buyer’s request,the seller agreed to charter a vessel at buyer’s account.When the date of shipment became due,the seller was still unable to get a vessel for shipment.The buyer not only disagreed to modify the date of shipment,but also cancelled the contract and claimed for loss,because the seller failed to effect shipment within the time stipulated in the contract.Is the seller responsible for failure to effect shipment for his inability to charter a ship?Please give brief reasons for your decision.